Hi all. I tried on my cardigan after clue 3 and it's too tight in the armpits. Does anyone know how I can fix this? I'm currently doing the size 7. Any help is appreciated!

These are the colors I started with. I'm holding each row together. I'm kind of confused because the notes and video say to have contrasting colors, but then a color to blend them together? So I tried my best with that. But now I feel like it's all wrong. I didn't do a color work swatch, and I feel like it isn't contrasting enough. I'm really struggling. Any help is appreciated!